360 Systems MAXX2400HD - Manual (Page 79)

Page 78 MAXX-2400HD Owner’s Manual
Bit Rates of Transferred Files Reported in the Clip Navigator
JPEG2000 as implemented in the MAXX-HD is a variable bit rate compression technology.
What this means is that the actual bit rate (amount of video data) that is created is dependent
on the level of detail in the images in the video frame being encoded.
The Video Compression Max Bit Rate setting is only a limit. The actual bit rate is determined
by the encoder on a frame by frame basis.
When a clip is first recorded, the GUI displays the Max Bit Rate value that was in effect when
the clip was recorded.
Files that are transferred as .vfc files maintain this value.
Files that are transferred as .mxf do not carry this value, so the GUI will display the actual
calculated average bit rate of the file as a function of its size relative to its duration. Therefore
it is normal to see variation between the original and a transferred copy of the file. It does not
mean that the content of the encoded video has been changed in any way.
Supported File Types
MAXX recognizes media file types by their file extension. It is important that the file extension
properly identifies the file content. Attempts to send a file in one format but masquerading as
another due to a wrong file extension may result in undefined behavior.
It is also true that file extensions such as .mxf can contain many different formats of video and
audio. The MAXX will only accept files that contain compatible formats as defined below.
Always test file import before depending on it for broadcast. Some formats allow wide
variation in the structure of files, and the parameters used in the video compression. MAXX-
HD will not accept all possible variations; always test files from new sources before going on
air.
The following formats are supported:
JPEG-2000 (.mxf)
JPEG-2000 files wrapped in the .mxf format. The mxf type is Operational Pattern OP1a. The
audio is 24-bit 48KHz PCM (uncompressed) in 8 individual tracks.
These files are compatible with the Edius non-linear editing program from Grass Valley. See
the next section for more information.
JPEG2000 format .mxf files from the Grass Valley Infinity camcorder are also compatible.
JPEG-2000 (.vcf)
JPEG-2000 files are also available in .vcf, a proprietary 360 Systems format. This is a very
simple collection of the native component files. It has some minor performance advantages
over .mxf and can be useful in certain applications. It is not recommended in applications
where there are many subclips created as the files contain all of the data regardless of the
settings of the head and tail pointers. A four second clip taken from a 1 hour file will contain
the entire hour of data.
In automation controlled systems that create subclips by reference to a single master file, this is
the preferred file type to use for mirroring content between servers or to backup storage. It is
also the format used by Telestream Flip Factory to transcode files to and from the MAXX server.